Oil coming out of muffler threads

[roccus]

I have some black oil coming out of my muffler on rebuilt MS260 was reading some of the threads here on it seems many say it could be from the case gasket in the oil tank area gone bad. If it was the case gasket would it hold pressure and vacuum? My saw holds pressure and vacuum perfectly. This saw has a new top end on it and I have so far only run it for maybe 15 minutes could it be that it has not seated in yet causing this? It seems to run real good but if I have the carb to rich would this pump oil out the muffler?

It is not flooding out or anything it starts easy just a few pulls when cold usually 2 pulls on full choke then 1 pull on 1/2 choke.

 

[grizz55chev]

Run it like you stole it.

 

[Full Chisel]

Might be tuned too rich or the metering lever in the carb is set too high.

 

[roccus]

Well I leaned it out a bit and it seems to have helped... I know I am running a little rich as it is a new iop end and figure it best to be rich during first couple of tanks for break in. So if the crank case gasket is letting go to allow oil to push out the muffler would it hold pressure and vacuum on the leak down test?

 

[roccus]

Another thought... this saw sat around for awhile before I got it wonder if there was oil in the crank case that is now blowing out and it just needs to run it's course to clean out? The first time I fires the saw after the rebuild I had a small puddle of oil sitting on top of the crank case under the muffler I don't seem to be getting puddles their now just more pin head sized droplets spitting out. I have now run almost a 1/2 tank gas through it since rebuild if there was excess oil in the crank how long would it take to push out?

 

[pioneerguy600]

Give it a couple tanks of run time, the rings should seat and the cylinder clean up. If it were the crankcase gasket it would not hold vac, possibly hold pressure after the oil tank was also pressurized. You could empty the bar oil and leave the cap off, run both vac and pressure tests then but its not likely the case gasket.

 

[roccus]

Give it a couple tanks of run time, the rings should seat and the cylinder clean up. If it were the crankcase gasket it would not hold vac, possibly hold pressure after the oil tank was also pressurized. You could empty the bar oil and leave the cap off, run both vac and pressure tests then but its not likely the case gasket.

Thanks I really needed some good news!! I want to sell this saw but don't think I should sell it without knowing if it's ok this was a parts saw I got along with a running saw I hope to sell it to get something small and light. I will take the oil tank cover off and put some pressure to it to see what happens..... note to self when doing a pressure test in future always remove oil cap

 

[Wood Doctor]

Sell it for something small and light? Seems to me like this MS260 is already there.

Hang onto it.

 

[roccus]

Sell it for something small and light? Seems to me like this MS260 is already there.

Hang onto it.

I have the other ms260 I will keep.. when I say small and light I am thinking something not over 12"bar in the size weight class of a mini mac

 

[blsnelling]

If black oil continues to come out of the muffler, then the saw is likely tuned too rich.

 

[Ted Jenkins]

I can remember two times this issue coming up recently. Most likely there is nothing wrong with the saw probably the fuel is adjusted rich which will cause at least some of the problem. If the saw is NOT under a load it can send unburned oil to the muffler because the combustion chamber is not at the ultimate temperature. There could be residual oil in the muffler and is now just getting blown out. Two tanks full of fuel and hard cutting should clear it up. Are there smaller saws than a MS 260? I always thought they were the smallest made. Thanks

 

[roccus]

Well can I ask you all this... with the facts I have laid out with it passing leak down test and all would you consider buying a saw like this with a bit of oil spitting out the muffler and feel confident it should be ok or would you run away from it??

 

[StihlNick]

Depends on what you were asking for it. Common folk mainly only care what it looks like anyways...

 

[Little Al]

Are you running a rich Oil/fuel nix ? the old saws in the 25/1 & thicker mixes usually gobbed oil from the exhaust the older bikes were the same I would take off the muffler & clean the inside refit & run it.

 

[Sammyp]

If I were selling it I'd probably break it in, then re-tune it and run hard for a tank. this should clear it out, if not then maybe you do have a problem (doesn't sound like it though or you'd have other symptoms/problems)

 

[blsnelling]

It should not be tuned that rich even for break-in.

 

[roccus]

Not sure if it makes any difference or not.. I use Stihl 50:1 oil mix with aviation fuel

another thing about this saw I have worked on a couple other stihl saws and when I have pulled the mufflers they have carbon build up in them which would be expected but the muffler on this saw has baked oil lining the inside of the muffler and cover so I wonder if this saw has been pushing oil out for awhile

 

[pioneerguy600]

I would clean that muffler out and then re tune the saw a little bit leaner each tank until it reaches the sweet spot. The oil spitting should stop by then.

 

[roccus]

Thanks Pioneer thats what I'll do... turning low idle in leans and high speed out leans right?

 

[grizz55chev]

Wrong.